The invention relates to a method utilized in a photomechanical scanner or the like for scanning and recording an original picture, and more particularly to such a method that is adapted to produce synthesized duplicates of said picture by means of two kinds of digital signals, one of them being a series of signals representing the picture of continuous tone while the other representing letters or characters of discontinuous binary tone such as white and black.
The picture scanning and recording apparatuses generally should have some kinds of editing functions. For example, a plurality of original pictures are to be recorded on a single photosensitive material in accordance with a predetermined layout. Further in the other cases, a continuous tone picture and a letter or figure with binary tone are synthesized to give a duplicate of desired layout. The letters or characters consist of fine and short lines giving binary electronic signals when they are scanned. A higher resolving power is therefore needed in scanning the letters or characters than in scanning the pictures. If, however, the higher resolving power were applied also to the picture of continuous tone, the overall processing time whould become much longer than that theoretically needed. This is an undesirable disadvantage for the abovesaid apparatus and method. Furthermore, such excessive power would also need an excessively large capacity of memory devices such as magnetic discs that are usually utilized in processing and layout operation of the electronic data produced for the above picture and the letters. The processing time would become increasingly longer because of such excessive capacity of said memory devices.